A Word, Please: A look at the em dash, the hyphen and their rarely seen cousin, the en dash

For as long as I can remember, I’ve been giving this note to my editing clients: “Replace floating hyphen with proper em dash.” It comes up when I’m proofreading images, like PDFs, and I see a hyphen with just a space on either side connecting two parts of a sentence – like this. But it wasn’t until very recently someone asked me about the term “floating hyphen.” Is that a real thing?

Of course it is, I said. Then I googled it and learned that, apparently, I had made the term up. But my point remains true: A hyphen is not an em dash. Nor is it an en dash. Each of these three punctuation marks has its own special job.

Em dashes, often simply called dashes, are sentence punctuation — a way to connect ideas and phrases and clauses. If you don’t want to use them, you don’t have to. Commas, parentheses and colons can usually get your point across in any spot where you might use a dash.

But if your sentence already has enough commas or if you want to create visual emphasis — like this — you can use em dashes to signal a change in sentence structure or thought. Or you can use em dashes to set off parenthetical thoughts — and who doesn’t love those? — in a sentence. They can also set off lists of items — names, places, things — mid-sentence or at the end. You can even use em dashes for dialogue, datelines or taglines or to show that speech was cut off mid-sentence.

Personally, I consider it a mistake to use an em dash between complete clauses — this sentence is an example. A period or possibly a semicolon would be better. But not everyone agrees with me.

News publications usually put a space on either side of an em dash — making it sort of float. Book and magazine publishing usually omit the spaces—their dashes touch the word on either side. Both are correct.

To make an em dash on a Mac computer, you type the hyphen key while holding down the shift and option keys. On a PC with a number pad, you can type the minus key while holding down the control and alt keys. In many word processing programs, you can just type two hyphens then the space bar and auto correct will make an em dash for you. All these systems offer other ways to make em dashes, too.

Unlike em dashes, hyphens are not sentence punctuation. They’re word builders. They connect words with other words, numbers, prefixes and suffixes to create terms like “forward-looking” or “pre-1950” or “full-time” or “e-reader.” You can use them to build your own multiword adjectives, as in a “true-crime obsession.” Some terms already contain hyphens in their proper spelling, which you can find in a dictionary, as in “good-looking” and “jack-of-all-trades.”

En dashes, which work more like hyphens than like em dashes, are rare. In most newswriting, they don’t exist at all. Old-school newswires couldn’t transmit them properly and so en dashes never became part of news editing style.

Book and magazine publishing will use an en dash, which is longer than a hyphen but shorter than an em dash, as a sort of uber hyphen. For example, they can connect two terms that already have hyphens in them, like in a semi-private–semi-public entity. They’re also used in place of hyphens to connect numbers with words or prefixes, like pre–1800, and for ranges and sports scores, like “the Dolphins won 10–7.” But a hyphen can do all these jobs nicely if you’re not working in an en dash world. To make an en dash on a Mac, hold down the option key then press the hyphen key. On a PC, hold down control and press the minus sign on a number pad.

June Casagrande is the author of “The Best Punctuation Book, Period.” She can be reached at JuneTCN@aol.com.

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